1. Field of the Invention
This invention relates to a sputtering apparatus, and more particularly to a sputtering apparatus that can judge whether or not a prescribed film deposition process has been satisfactorily performed on the basis of the detection results of the abnormalities in the sputtering process.
2. Description of the Prior Art
In recent years, a compact disk (hereinafter referred to as a CD) and a laser disk have been widely used to record a large amount of digitized sound and image information. The substrate of the CD is made of transparent synthetic resin such as polycarbonate and the like. A large number of so-called pits are formed on the surface of the substrate in accordance with digital information of "1" or "0". Further, an aluminum thin film having a high light-reflectivity is deposited on the pits-formed surface of the substrate by use of a sputtering technique. The thus recorded information can be read by the presence or absence of the reflected light of a laser light beam applied to the CD. The aluminum thin film deposition pep a single sheet of the substrate can be performed in a relatively short time. Thus, the continuous film deposition process with respect to a large number of substrates can be achieved.
A conventional sputtering apparatus generally has a configuration shown in FIG. 12 and FIG. 13. Specifically, digital information of "1" or "0" is recorded on the substrate by use of a press-molding technique, which is performed in a molding apparatus 1. The information-recorded substrate 4 is transferred by a first handling machine 2 into a film deposition apparatus 3, which has a configuration shown in FIG. 13. In FIG. 13, a light-reflecting film is deposited on the surface of the thus transferred substrate 4 in a film deposition chamber 31 (which is a vacuum chamber) by use of a sputtering source 32. The sputtering source 32 incorporates a target 33 disposed opposing to the substrate 4. In FIG. 12, a DC power source 34, which supplies pulse-shaped sputtering power of about 15 KW at a maximum, is connected to the film deposition apparatus 3. Specifically, the sputtering power is applied across the target 33 and the substrate 4 so as to perform the sputtering process in the film deposition chamber 31, as shown in FIG. 13. Further, a control unit 5 is connected both to the DC power source 34 and the film deposition chamber 3 so as to control a series of sputtering processes.
However, in the above-described conventional sputtering apparatus, there is not provided judging means for immediately judging whether or not the sputtering process in the film deposition apparatus 3 has been normally performed and an aluminum thin film has been satisfactorily deposited on the substrate 4. As shown in FIG. 12, the film deposition apparatus 3 is incorporated in the manufacturing line consisting of the subsequent second handling machine 6 followed by a protective film-forming apparatus 7.fwdarw.a third handling machine 8.fwdarw.an inspection apparatus 9. Thus, the film-deposited substrate 4 will not be inspected until it reaches the final step of the manufacturing line, i.e., the inspection apparatus 9. In the inspection apparatus 9, automatic inspection items are processed which include a function test to automatically judge whether or not the information has been satisfactorily recorded on the CD. However, the items do not include an automatic inspection step to automatically inspect whether or not an aluminum thin film per se has been satisfactorily deposited. Assume that the results of such function test are satisfactory; however, the aluminum thin film per se has uneveness or black stains which damage the appearance of the CD as salable merchandise. In this case, such CD must be removed as a defective product. Therefore, after the completion of the entire manufacturing processes, the finished CDs must undergo the prescribed visual inspection performed by human operators. In other words, even when an aluminum thin film has been unsatisfactorily deposited on the substrate 4 in the film deposition apparatus 3, such defective substrate 4 must pass through the subsequent processes including the protective film formation. This consumes wasteful time in the subsequent processes, and increase the load on the final inspection process. Further, a large number of defective CDs might be produced, which cannot be detected in the final inspection process. As described above, in the conventional sputtering apparatus, judging means are not provided for immediately judging whether or not the prescribed film deposition by sputtering has been satisfactorily performed. Thus, a large number of defective products might be unnecessarily transferred into subsequent processes. This inevitably deteriorates the yield of the products and decreases the efficiency of the manufacturing line.